Use of a certain compound in preparing a medicament used in treating mood disorder, particularly, depression is known (WO00/61125 gazette).
In addition, a protein (Gm1 protein) is known (US 2005/260595), the protein containing: a domain having high sequence identity with a GTP-binding site and a GTPase activation site which are conserved among G-protein α subunits, and an amino acid sequence having high sequence identity with a trimer-forming domain conserved among G-protein α subunits. The protein is reported to be involved in intracellular signal transduction due to G protein-coupled receptor (GPCR) stimulation, and expressed in human brain, thymus, testis, spleen, small intestine, uterine and heart. And, a method for screening a cellular signal transduction regulating substance using a polynucleotide encoding the protein is disclosed.